玄数

negative   负

• Less than zero.
• A quantity, number, angle, velocity, or direction in a sense opposite to another of the same magnitude indicated or understood to be positive.

net weight   净重
Tthe weight of the contents only, excluding the weight of the container or packaging.

nonagon   九边形
A polygon having nine angles and nine sides.

normal   法线；正交的

• A perpendicular line or plane, especially one perpendicular to a tangent line of a curve, or a tangent plane of a surface, at the point of contact.
• The portion of this perpendicular line included between its point of contact with the curve and the x-axis.

normal distribution   正态分布

not equal   不等于

notation   符号

nought   零

number   数字

number line   数线

number pattern   数字模式

number sense   数感

number system   数制
Any system of naming or representing numbers, as the decimal system or the binary system.

numeral   数字

numerator   分子